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Message-ID: <20160219173522.2495a814@gandalf.local.home>
Date: Fri, 19 Feb 2016 17:35:22 -0500
From: Steven Rostedt <rostedt@...dmis.org>
To: Tom Zanussi <tom.zanussi@...ux.intel.com>
Cc: masami.hiramatsu.pt@...achi.com, namhyung@...nel.org,
josh@...htriplett.org, andi@...stfloor.org,
mathieu.desnoyers@...icios.com, peterz@...radead.org,
linux-kernel@...r.kernel.org
Subject: Re: [PATCH v13 06/29] tracing: Add needs_rec flag to event triggers
On Fri, 19 Feb 2016 14:30:13 -0500
Steven Rostedt <rostedt@...dmis.org> wrote:
> > @@ -1333,6 +1339,7 @@ struct event_command {
> > char *name;
> > enum event_trigger_type trigger_type;
> > bool post_trigger;
> > + bool needs_rec;
>
> Note, from what I understand, gcc sucks with bool in structures. Best
> thing to do here is to create a "int flags" field, and check the result
> with masks.
>
> You don't need to update this patch (I'm still working on the series),
> but a patch on top of these may be necessary. I could add the patch too.
>
I've added this patch after patch this patch. What do you think?
-- Steve
diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index 789e88ab5acd..f60c0444ef1e 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -1272,30 +1272,7 @@ struct event_trigger_ops {
* values are defined by adding new values to the trigger_type
* enum in include/linux/trace_events.h.
*
- * @post_trigger: A flag that says whether or not this command needs
- * to have its action delayed until after the current event has
- * been closed. Some triggers need to avoid being invoked while
- * an event is currently in the process of being logged, since
- * the trigger may itself log data into the trace buffer. Thus
- * we make sure the current event is committed before invoking
- * those triggers. To do that, the trigger invocation is split
- * in two - the first part checks the filter using the current
- * trace record; if a command has the @post_trigger flag set, it
- * sets a bit for itself in the return value, otherwise it
- * directly invokes the trigger. Once all commands have been
- * either invoked or set their return flag, the current record is
- * either committed or discarded. At that point, if any commands
- * have deferred their triggers, those commands are finally
- * invoked following the close of the current event. In other
- * words, if the event_trigger_ops @func() probe implementation
- * itself logs to the trace buffer, this flag should be set,
- * otherwise it can be left unspecified.
- *
- * @needs_rec: A flag that says whether or not this command needs
- * access to the trace record in order to perform its function,
- * regardless of whether or not it has a filter associated with
- * it (filters make a trigger require access to the trace record
- * but are not always present).
+ * @flags: See the enum event_command_flags below.
*
* All the methods below, except for @set_filter() and @unreg_all(),
* must be implemented.
@@ -1340,8 +1317,7 @@ struct event_command {
struct list_head list;
char *name;
enum event_trigger_type trigger_type;
- bool post_trigger;
- bool needs_rec;
+ int flags;
int (*func)(struct event_command *cmd_ops,
struct trace_event_file *file,
char *glob, char *cmd, char *params);
@@ -1360,6 +1336,49 @@ struct event_command {
struct event_trigger_ops *(*get_trigger_ops)(char *cmd, char *param);
};
+/**
+ * enum event_command_flags - flags for struct event_command
+ *
+ * @POST_TRIGGER: A flag that says whether or not this command needs
+ * to have its action delayed until after the current event has
+ * been closed. Some triggers need to avoid being invoked while
+ * an event is currently in the process of being logged, since
+ * the trigger may itself log data into the trace buffer. Thus
+ * we make sure the current event is committed before invoking
+ * those triggers. To do that, the trigger invocation is split
+ * in two - the first part checks the filter using the current
+ * trace record; if a command has the @post_trigger flag set, it
+ * sets a bit for itself in the return value, otherwise it
+ * directly invokes the trigger. Once all commands have been
+ * either invoked or set their return flag, the current record is
+ * either committed or discarded. At that point, if any commands
+ * have deferred their triggers, those commands are finally
+ * invoked following the close of the current event. In other
+ * words, if the event_trigger_ops @func() probe implementation
+ * itself logs to the trace buffer, this flag should be set,
+ * otherwise it can be left unspecified.
+ *
+ * @NEEDS_REC: A flag that says whether or not this command needs
+ * access to the trace record in order to perform its function,
+ * regardless of whether or not it has a filter associated with
+ * it (filters make a trigger require access to the trace record
+ * but are not always present).
+ */
+enum event_command_flags {
+ EVENT_CMD_FL_POST_TRIGGER = 1,
+ EVENT_CMD_FL_NEEDS_REC = 2,
+};
+
+static inline bool event_command_post_trigger(struct event_command *cmd_ops)
+{
+ return cmd_ops->flags & EVENT_CMD_FL_POST_TRIGGER;
+}
+
+static inline bool event_command_needs_rec(struct event_command *cmd_ops)
+{
+ return cmd_ops->flags & EVENT_CMD_FL_NEEDS_REC;
+}
+
extern int trace_event_enable_disable(struct trace_event_file *file,
int enable, int soft_disable);
extern int tracing_alloc_snapshot(void);
diff --git a/kernel/trace/trace_events_trigger.c b/kernel/trace/trace_events_trigger.c
index cbb7ee531983..d67992f3bb0e 100644
--- a/kernel/trace/trace_events_trigger.c
+++ b/kernel/trace/trace_events_trigger.c
@@ -81,7 +81,7 @@ event_triggers_call(struct trace_event_file *file, void *rec)
filter = rcu_dereference_sched(data->filter);
if (filter && !filter_match_preds(filter, rec))
continue;
- if (data->cmd_ops->post_trigger) {
+ if (event_command_post_trigger(data->cmd_ops)) {
tt |= data->cmd_ops->trigger_type;
continue;
}
@@ -506,8 +506,8 @@ void update_cond_flag(struct trace_event_file *file)
bool set_cond = false;
list_for_each_entry_rcu(data, &file->triggers, list) {
- if (data->filter || data->cmd_ops->post_trigger ||
- data->cmd_ops->needs_rec) {
+ if (data->filter || event_command_post_trigger(data->cmd_ops) ||
+ event_command_needs_rec(data->cmd_ops)) {
set_cond = true;
break;
}
@@ -1035,7 +1035,7 @@ stacktrace_get_trigger_ops(char *cmd, char *param)
static struct event_command trigger_stacktrace_cmd = {
.name = "stacktrace",
.trigger_type = ETT_STACKTRACE,
- .post_trigger = true,
+ .flags = EVENT_CMD_FL_POST_TRIGGER,
.func = event_trigger_callback,
.reg = register_trigger,
.unreg = unregister_trigger,
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